The invention relates to a micro switch and, more particularly, to a micro switch having bi-directional operation to switch on/off the electrical contact point.
A conventional small-sized micro switch with bi-directional operation is known to be more easily for use if the activation interval (an interval from activating the electrical contact point to deactivating the same) of its pushbutton can be longer. Therefore, when making a micro switch, the manufacturers will set the pivot point of the pushbutton at the endmost portion of the main body. Then, the operation portion of the pushbutton, which is used to press the resilient element downwards to a contact portion, is provided at the opposite side of the pivot point. Therefore, the length of activation interval is determined by how the pivot point of pushbutton is located. As for positioning the pivot point of pushbutton, a positioning element can be scaled inside the concave portion at an opening end""s edge on the main body so that the pushbutton can be prevented from detaching.
On the other hand, in order to improve the problems of high cost in positioning element and assembling labor caused by the positioning method of pushbutton""s pivot point, a solution is proposed; that is, a semicircle-shaped hole is provided, which is formed by an arc edge and a straight-lined edge capable of free rotating to support the pivot axis of pushbutton and is located at two sides of the main body of micro switch. Then, the pivot axis of pushbutton will be coaxial to the semicircle-shaped hole at two sides of the pushbutton. After that, a fan-shaped protrusion is provided, which is smaller than the open angle of semicircle-shaped hole, and the fan-shaped protrusion is embedded in the semicircle-shaped hole to form a micro switch that can save the cost of a positioning element. Unfortunately, there are still other problems involved with the micro switch, which are discussed as below:
1. The length of activation interval is subjected to the size of fan-shaped protrusion and semicircle-shaped hole that should be matched to each other. If the angle formed by the fan-shaped axis has been diminished, the activation interval of pushbutton can then be lengthened. However, the diminishing action will lower the assembling force necessary for the fan-shaped protrusion to be embedded into the semicircle-shaped hole, which eventually will make the pushbutton prone to be detached more easily when the resilient element is restoring its resilience and pushing back upwardly. In addition, comparing to the semicircle-shaped hole, the rotating movement made by the fan-shaped protrusion can limit the activation interval more. Therefore, such improvement cannot actually increase activation interval.
2. In order to prevent from the above-mentioned detachment of pushbutton as well as to prevent the pushbutton from shaking, a brake element and a thin panel are provided on the main body and the pushbutton. However, since the volume of micro switch is very small itself, forming a brake element and thin panel does very little in reinforcing strength. Besides, degree of product precision is hard to be achieved because of small volume. Therefore, product yielding will not be good enough, and on the other hand, assembling cost might be increased since degree of product precision is hard to be controlled.
In viewing the above problems, the object of the invention is to provide a design that doesn""t have to lengthen the activation interval of semicircle-shaped hole like what is done in the prior art; instead, a round hole is provided at two sides of the main body corresponding to the pivot point of pushbutton, and a place-in slot is provided extending from the round hole to the opening end of the acceptance room; besides, a gap is provided on the sidewall of main body adjacent to the round hole, extending to the opening end of the acceptance room; in addition, a guiding slanting face is formed at the lower edge of pivot point of pushbutton; therefore, through flexible force formed by the gap and through the guiding slanting face that makes it easy for the upper part of pivot point to be conjoined to the round hole in an embedding-in manner, a micro switch with longer activation interval is then completed.
Another object of the invention is to abandon the prior method of reinforcing positioning by utilizing a flat object such as a brake element and a thin panel applied in the prior art because the method is lacking good strength and good control in degree of product precision; instead, a confining portion is provided on another sidewall of main body opposite to the gap, and a top-ending portion is provided extending from the pushbutton corresponding to the confining portion. After the place-in face of top-ending portion has been smoothly conjoined to the confining portion, a positioning method by utilizing a press-top face as a block can effectively prevent the pushbutton from detaching when the pushbutton is pushed by the resilient element due to restoring resilience.